Give x+3y=6 and 3x+5y=7, what is 8x-2y?

We'll have to determine x and y, to find the value of the
difference 8x - 2y.

We'll multiply the 1st equation by
-3:

-3x - 9y = -18 (3)

We'll
add (3) to (2):

-3x - 9y + 3x + 5y = -18 +
7

We'll eliminate like
terms:

-4y = -11

y =
11/4

x = 6 - 3y

x = 6 -
33/4

x = (24-33)/4 => x =
-9/4

We'll determine the value of the
difference:

8x - 2y = 8*(-9/4) - 2*11/4 = -18 -
11/2

8x - 2y =
-47/2

The value of the difference is 8x - 2y
= -47/2.